Radiotherapy Physics Perspective2019/12/11 · Physics and Radiobiology 13 physicists 2 Physics...
Transcript of Radiotherapy Physics Perspective2019/12/11 · Physics and Radiobiology 13 physicists 2 Physics...
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Centre for the Clinical Application of Particles
Radiotherapy Physics Perspective
Dr Ruth McLauchlanDepartment Radiation Physics & Radiobiology
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Outline
Who are we?
What do we do?
What equipment do we have?
Working with CCAP so far
Future Developments in RT
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Who are we?
Department of Radiation Physics and Radiobiology 13 physicists
2 Physics assistants
2 trainees
3 Linac engineers
2 Mechanical workshop engineers
1 Mould room technical officer
1 Unsealed sources technical officer
Radiotherapy Planning Team: 9 Dosimetrists (since Oct 2019)
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What do we do?
Scientific support to Department of Radiotherapy Maintenance/QA of equipment
Calibration of equipment traceable to NPL following UK IPEM Codes of Practice
Advise on patient treatment planning including issues during treatment
Immobilisation/modality/ technique/imaging
Independent checking of patient treatment plans
Commission new equipment/implement new techniques
Clinical trials/audit
Teaching/training
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What do we do?
What are we treating?
What dose is/was delivered?
How will the tissues (tumour and normal tissue) respond?
Dept. of Radiotherapy treats >1800 patients per year
Delivering > 28000 # of EBRT
Delivering > 250 # of Brachy
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What equipment do we have?
2017 20196 Linear Accelerators (Varian) delivering 6/10 MV photons, 6/9/12/16/20 MeV electrons
2 x TrueBeam & 2 x SXi @ Charing Cross Hospital
3 x TrueBeam and 1 x STX @ Charing Cross HospitalMore advanced imaging and treatment delivery inc.2 x ExacTrac imaging systems & 2 x 6DOF couch
2 x SXi @ Hammersmith HospitalMV portal imaging/IMRT
Xstrahl Unit @ Charing Cross80/150/300 kV x-rays
HDR Brachytherapy unit @ HammersmithBasic cases
NEW HDR Brachytherapy unit @ Hammersmith
Complex planning
Philips Brilliance Big Bore CT scanner @ Charing Cross4DCT capability
TPS: Oncentra; Eclipse; ProSoma TPS: Oncentra; Eclipse; ProSoma -> RayStation
Access to MRI & PET
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Linear accelerator
http://www.int03.co.uk/vertual/demoes/varian.htm
http://www.int03.co.uk/vertual/demoes/varian.htm
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Modalities
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Equipment Calibration
Are we giving the dose as prescribed? Point dose measurement/calibration (ion chamber)
Photons – farmer chamber; pinpoint; diamond
Electrons – parallel plate NACP/Roos
Daily constancy checks Beamchecker
Confirm dose to patient Invivo dosimetry - diodes
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Patient Specific Verification
Independent dose calculation software - IMSure
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Patient Specific Verification
Independent dose measurement/fluence checks, e.g. PTW729 array, PTW SRS array & Octavius
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Patient Specific Verification
Portal Dosimetry Transit Dosimetry
Portal Dosimetry using calibrated EPID
Back-project dose projection
Use the patient rather than a phantom
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Accurate treatment set-up
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On-board imaging
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Working with CCAP so far
Image Guided Verification for the future Towards CBCT auto-match and analysis
CASE proposal BSc student project
EPSRC Discipline Hopping call investigated “Investigators must be academic employees
(lecturer or equivalent)…” FLASH-RT
Possibility of adapting linac at Hammersmith Stalled due to clinical need for machine
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Future Developments in RT
Treating small volumes/Hypofractionation/SABR Improved localisation
Imaging/Surface guided RT Immobilisation
Accurate dosimetry Adaptive Radiotherapy
Movement of tumour during delivery Shrinkage/growth of tumour
→ MRI linac FLASH RT
Linac Protons
Radiobiological planning